This invention relates in general to a workholder for a sewing machine for producing a stitch row in a workpiece according to a predetermined contour. The movably arranged workholder having a cutout essentially formed according to the stitch contour, is controlled with respect to the needle by means of a feeding device incorporating a linkage system and a control disc. In particular, a new workholder with additional workpiece clamping means is provided.
With advanced sewing automation, decorative stitches are applied on a workpiece or in conjunction with parts to be attached to such workpieces, such as a pocket for example. On the other hand, especially on blue jeans as well as other garment workpieces, labels are attached where the label attaching process requires a separate operation. Especially in an operation for attaching pockets in a symmetric arrangement to a garment, it may occur that one of the pair of pockets carries both a label and a decorative stitch row whereas the other pocket carries a decorative stitch row only. With application, both decorative stitch rows are of uniform profile except that area where the label is attached to the pocket as the label partially overlaps the decorative stitch row. Frequently such decorative stitches are characterized by closed stitch rows which are difficult to produce.
In U.S. Pat. No. 4,160,423 there is illustrated a sewing device for making slit facings of a garment such as a sleeve placket, for example. From this reference it is known to employ a workholder having a clamping plate, around which a closed stitch row is being produced. In order to render this possible, the clamping plate is tiltably situated at the workholder. Due to this arrangement there is achieved that the sewing head displaces the workpiece holder as the sewing head performs the last portion of the stitch row for closing the latter.
In general it is known to employ a frame-type workholder for the manufacture of a decorative stitch row in a workpiece. In such a type of workholder, the workpiece is clamped at its outer margin, so that there exists no restriction inside of the frame, as far as the movement of the needle with respect to the sewing area is concerned.
Accordingly, it is a main object of the present invention to create a frame-type workholder for a workpiece for producing a contoured stitch row having a decorative stitch row and a fastening stitch row for attaching a label to the workpiece in one operation.
It is a further object of this invention to construct a workholder of the aforesaid type and making it possible to produce the fastening stitch row over the total marginal circumference of the label.
Still a further object of this invention is to provide a workholder of the aforesaid type that assures the correct positioning of the label to be attached with respect to the decorative fastening stitch row.
Another important object of this invention is to create a workholder which can be employed without modification for generating a decorative stitch row in a workpiece or for generating a fastening stitch row to attach a label to a workpiece only.
Still another object of this invention is to provide a workholder for a sewing machine for increasing production while reducing the skill of the operator required for producing decorative stitch rows of complicated geometry but having a uniform appearance.
A further object of this invention is to provide a workholder of the aforesaid type to reduce the costs for producing such decorative stitch rows including label attaching where high and uniform quality is achieved.
Still another object of the present invention is to provide a workholder of the aforegoing character which is simple in construction and reliable in operation.